Question

If you had 3.45 x 10^14 atoms how many moles would you have?

Answer 1

Well, one mole of atoms is 6.02 x 10^23 atoms so ........?

Answer 2

Think about this. I'll bet if we asked this question about apples or oranges and never used the word atoms you would be able to work the problem. Try this. You have 36 apples. How many dozen is that. Well, a dozen is 12 so

36 apples x (1 dozen/12 apples) = 3 dozen
Notice that this is apples x (dozen/apples) and the answer comes out in dozen. That's because the apples unit cancels with apples in the numerator and apples in the denominator which leaves the unit dozen and that's what you want the answer in; i.e., dozen. The apples problem is the same thing but we aren't talking about things we can't see like atoms. We can see apples. And we know what a dozen is which is unlike a mole.